1. Field of the Invention
The present invention relates to a yarn winding machine, and more specifically to a doffing apparatus of an automatic winding machine having a frame, a plurality of winding units each carrying a yarn package, and conveying means to transport a full package.
In a known yarn winding machine having a plurality of winding units which move along an annular rail while winding, it is customary to perform the doffing operation at a stationary position by the rail. However, to perform the doffing operation separate from the winding units, each winding unit must wait to reach the doffing apparatus without the winding operation after a full package is formed at a random point along the rail, so that the operation time of the winding unit is decreased. Also, in the known machines, the doffing operation must be performed after a full package is removed from the guiding drum of the winding unit, so that the doffing interval, i.e., from the stopping of winding to restarting of winding, is relatively long.
2. Description of the Prior Art
U.S. Pat. No. 3,476,328 discloses a winding unit, in which the cradle arm is moved upwards to separate from the winding drum by engaging the end portion of the cradle arm with a cam. U.S. Pat. No. 3,311,311 discloses a winding unit, in which a horn-like arm is inserted under the spool to transfer the spool on the arm so that the spool is disengaged from the winding drum. These apparatus must provide means to vary the arm movement in accordance with the diameters of the full package. Also in U.S. Pat. No. 3,476,328 and U.S. Pat. No. 3,356,306 there are taught swing arms to push out the full package. However, the full package must be stopped after being disengaged from the guiding drum, so that some time loss is inevitable. Further, U.S. Pat. No. 3,476,328 provides a yarn guide wherein the package receiver and the cutter are separated, so that the yarn guide can miss and consequently a yarn connected package might be produced.